1. Field of the Invention
This invention relates to a transmission for use in automobiles, and more particularly to a transmission for use in front-wheel drive or rear-wheel drive automobiles with an engine transversely mounted therein, wherein an automatic speed change gear and a final reduction gear are incorporated in combination.
2. Description of the Prior Art
With a view to affording an automobile increased space, automobiles having front-engine, front-wheel or rear engine, rear-wheel driving systems have become recently popular. Such automobiles have many advantages, such as compactness in size, reduction in weight and reduction in fuel consumption.
If an automatic speed change gear providing four forward speed range drives and one reverse drive is incorporated in the transmission for use with a front-wheel drive automobile having a laterally mounted engine, in order to reduce fuel consumption and to reduce noise, the overall length of the transmission increases and may interfere with the suspension of the automobile. This presents a serious problem, particularly in so-called compact cars.
To cope with such a problem, a compact transmission for use in an automobile has been developed providing an automatic speed change gear with at least four forward speed range drives and a reverse drive which does not interfere with the suspension device of the automobile. Such transmissions are generally disclosed in U.S. Pat. Nos. 4,056,988 and 4,063,468.
In such a transmission, the first two forward speed ranges and reverse are considered an underdrive unit and the third and fourth forward speed range are considered an overdrive unit, each unit being contained in a separate case. The thrust forces acting on the overdrive unit and underdrive unit are each received by the respective cases through bearings. In a transmission using such bearings, where thrusts act in the same direction, the sum of the thrusts act on the bearings and cases. Such forces largely develop during stall conditions. These forces lead to a shortened service life of bearings and an accelerated deformation of the cases.